1. Field of the Invention
The present invention relates to sealable tamper evident plastic packaging and processes for making them.
2. Description of the Background
Packages made from single or multiple layers of a plastic or polymer material such as polyethylene, nylon or polyester, include arrangements for envelopes or mail packages that are used for the shipping of documents and objects via the U.S. mail or an overnight courier. These shipping packages or pouches are made from a single sheet of material that is folded upon itself and sealed along the edges to form a pouch. One end of the pouch is open, and one portion of the folded material is longer than the other to create a flap for closing over the open end of the pouch. Adhesive is provided on the pouch where the flap overlaps the side of the pouch to seal the pouch closed. These pouches, however, lack handles to facilitate carrying the pouch, or holes to facilitate mounting the pouch on a stand or post for storage or loading of the pouch. It is difficult to add handles or mounting holes to packages made from single (one or multiple-layer) sheet of plastic.
To illustrate, a prior attempt at a flexible sealable pouch is illustrated in FIGS. 1-3. A single sheet of flexible plastic material 100 is provided. On one side of the sheet 100 an adhesive strip 102 is attached. As seen in FIG. 3, the adhesive strip includes a tacky contact adhesive 302 covered by a removable plastic strip 304 that prevents adhesive sealing until the plastic strip is removed. In FIG. 1, the sheet of material has a top edge 110 and a bottom edge 108. A first fold line 104 is provided near the top edge, and a second fold line 106 is provided generally in the center of the sheet. Folding the sheet of material across the first fold line 104 and bonding the overlapping areas of material together along a bonding line 206 creates a header section 208. The first fold line 104 defines the top of the header. The entire side edges of the header 210 along the entire overlapping length and all the way to the overlapped top edge 110 of the header are heat sealed. A portion of the overlap 310 extends partially over the adhesive strip 102.
The sheet of material is then folded over the second fold line 106 and heat sealed along the entire length of both side edges 210. This forms a pouch area 212 having a front 306 and a back 308. The bottom edge 108 of the sheet is now at the opening of the pouch area 212. The tacky contact adhesive 302 is bonded to the inside surface of the back 308 of the pouch area 212. The front 306 of the pouch area overlaps most of the adhesive strip 212; however the flap portion 310 from the top fold is between the front 306 and the adhesive strip near the open edge 108. In use, the pouch front is pulled away from the back, and the desired contents are inserted into the pouch. To seal, both the pouch front 306 and top flap 310 have to be pulled away from the adhesive strip 102 to remove the plastic covering strip 304. The top flap has to be sealed against the adhesive 102 followed by the pouch front. This is a difficult procedure that is further complicated when the pouch contains large or bulky items. In addition, the top edge or opening 108 of the pouch is not in contact with the adhesive, making is possible for this edge to become hooked or snagged or creating handling problems. In addition, these pouches lack handles to facilitate carrying the pouch, or holes to facilitate mounting the pouch on a stand or post for storage or loading of the pouch. This is important in the pharmaceutical context because pharmacists need a convenient dispenser for the bags while filling them with prescriptions, and dropping the bag can rupture the contents. It is difficult to add handles or mounting holes to packages as above made from single (one or multiple-layer) sheet of plastic. Therefore, a plastic tamper evident pharmaceutical pouch is desired that overcomes these limitations.